Myoepithelioma of a minor salivary gland of the cheek: case report

Abstract

Myoepithelioma is a rare neoplasm of the salivary glands, generally occurring in the parotid gland and less often in the minor accessory salivary gland of the oral cavity. The histological appearance includes solid, myxoid and reticular growth patterns. Vimentin and S-100 protein are very sensitive but non-specific immunohistochemical markers of neoplastic myoepithelium. Conservative surgery is the treatment of choice. A case of myoepithelioma of the minor salivary gland of the cheek with low grade malignancy is described, focusing on clinical behaviour, histopathological and immunohistochemical features and differential diagnosis.

Fig. 1

Axial contrast-enhanced CT scan demonstrated a solid, well-circumscribed mass (2x3.5 cm) in right cheek, laterally to horizontal tract of jaw, with homogeneous enhancement; the lesion displaced, but did not infiltrate, the superficial veins and did not appear to involve the bone.

Fig. 2

Myoepithelioma of minor salivary gland of cheek: tumour is composed of small and/or medium spindle-shaped cells, differently interlaced, with eosinophilic cytoplasm, that occur in sheets or swirls and have round to oval nuclei with finely dispersed chromatin. Stroma is myxomatous (haematoxylin and eosin, [H&E], x16).

Fig. 3

Immunohistochemical study (25x). Myoepithelial cells stain strongly positive for vimentin and focally for S100 and CD100 protein.